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A
plea for centrally supported, orthophoto
based, cadastral system and management of
change |
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Cadastral
surveys are specially designed large scale surveys,
generally on 1:4000 scale which are linked to
land ownership and property. In case of urban
cadastral surveys, the scales may be as large
as 1:500 to 1:4000. This paper is, however, emphasizing
the rural and village properties. The urban cadastre,
although very vital needs a separate and detailed
discussion.
In practical proportion of the importance,
the surveys and mapping oriented
activities form only 10% of the total cadastral
related work. The remaining
90% really fall in the realm of generating appropriate
land records. The importance of these land records
is, of course, very high because it is only through
the cadastral maps and land records that the owner
gets legally
linked to his property. This property may be a
cultivated field, house or a fishing pond. The
fact of the matter is that lack of updating the
maps and the land records have given rise to the
innumerable court cases. The property related
court cases are thriving because of the reduced
importance of the cadastral surveys.
Can the modern technology of`Geomatics’
(extended version of surveying and mapping) and
the body of knowledge of management of change
help in mitigating the major lacunae in the professional
practice
of cadastral surveys and land records? The answer
is emphatic YES. It is with this perspective that
this paper has been prepared.
Push From Politicians, Press and Parliament (PPP)
It is a common fact that the present `politics
of election’ is centred around the theme
of `development’. If development is the
`push of the politicians’, the cadastral
surveys (and better technology) will become most
relevant and urgent. The Government can ill afford
to ignore the importance of value adding / improvement
in the property related surveys. The fact is that
cadastral surveys are the only unique surveys
of their kind, which are directly connected with
the masses.
If there is development, can cadastral surveys
be left behind?
Management of Technological Changes
One has to see the introduction of new
technology as an important part of the `change-process’.
The change has not only to be `right’ but
MISRAshould also be made more `acceptable’
to all the stakeholders of the process. Special
thought has, therefore, to be given for bringing
lasting changes in cadastral surveys in India.
The scope of this paper is, however, limited to
the surveys and mapping technology (ies). The
subsequent changes in the area of generating land
records is not attempted for want of space. |
Historical Perspective of Cadastral
Surveys in India
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Revenue
surveys were initiated by East India Company towards
the end of 18th Century primarily to establish
the `domain of their influence’ through
the collection of revenue from the estates. These
estates were rather scattered so only village
boundaries were established by the traverse method
of surveying. The inside details of properties
were left to local surveys. Survey of India as
a Department of Government of India, established
in 1767, was fully involved in the process till
1904.
Following the recommendation of the 1904 Committee
of Government of India, the cadastral surveys
were delegated (in my opinion, abdicated!) to
the States. The States evolved their
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The
Management of Change
The
change is bound to come due to the application
of new technology whose appropriateness is to
be proved through reducing cost, producing more
village maps in a given time and generating more
timely and reliable information. In other words,
the new technology has to be:
• Professionally right i.e. follows principle
of surveying
• Socially acceptable, by a vast majority
of land-owners
• Economically viable i.e. the new technology
should be less costly when compared to the past
methodology.
Example: The new technology may bring some changes
in the area of plots which may be less than what
is shown on the old map or Field Measurement Book
(FMB). The authorities will have to adopt acceptable
approach or strategy of gradual change with adequate
time interval before new measurements are adopted.
The `betterness of change’ has to be proved,
not through an authoritarian approach but by slow
campaigns and appropriate communication strategy.
Even elected representatives should be educated
for the changes dictated by the technology.
In other words, the changes should not only be
`right’ but should also be acceptable. |
own legal
system of revenue surveys. The Northern States
of U.P., M.P., Bengal, Rajasthan, Punjab established
‘graphic output’ of surveys as the
legal document whereas the Southern states recognised
Field Measurement Book (FMB) as the legal document.
There was little input from Survey of India. In
1929, Survey of India took to first aerial survey
in Malda district of Bengal which was carried
out to produce revenue maps on 16 inches to 1mile
scale. But no serious attempt was made to transfer
the technology to the States. Again during 1939-1945
war Survey of India adopted air-survey methods
and later Photogrammetry in 1954. The situation
regarding the technology in the States remained
the same as was available in 1904.
Later, in 1964, the first State Cadastral Surveys
conference was held in Mussoorie which was motivated
by the concept that State Department of Settlement
Surveys and Land Records should exchange ideas
on the subject to provide technical solutions
to, for example, town surveys etc. The conferences
have been regularly held but the progress has
been rather slow. The author, while serving Survey
of India organized a Demonstration Seminar for
the technology of Aerial Photography, Photogrammetry,
Photo Rectification and Records Management etc
in 1973. The Government of India (Ministry of
Rural Development) has recently taken up computerization
of records and introduction of other relevant
technologies quite enthusiastically. This has
been motivated, due to the success of Madhya Pradesh
in utilizing the aerial photography and rectification
process for substituting their plane-table (graphical
records), improving their record keeping systems
and making the whole system farmer – friendly.
This process of technology-
transfer from Indian Institute of Remote Sensing,
Dehradun to the Commissioner of Land Records,
Gwalior has been a successful example
of the transfer of technology.
Meanwhile, new contemporary technologies namely,
Global Positioning System (GPS) and Orthophoto
Mapping are being harnessed for projects in India.
The same technologies could prove very beneficial
to the cadastral mapping.
It is suggested that Survey of India should again
take the professional lead to `hold-hands’
of States in so far as technological leadership
and contributions are concerned. |
| The
Proposed Technology For Cadastral surveys |
| A cadastral map (or for that
matter any map) will generally have the following
characteristics: |
| Geometry
(Accuracy of Position) By GPS |
The geometry
of the map is achieved through use of appropriate
instruments. The traditional technology of traversing
for establishing ground stations on the periphery
of the village revenue map will be replaced by
GPS. GPS is very accurate and simple for establishing
control points.
GPS technology in `differential mode’ (DGPS)
should be employed to accurately fix the `most
sacred’ control points i.e. `tri-junctions’
(where boundaries of three or more villages meet).
The main advantage of GPS technology is that ground
control stations can be provided even for isolated
villages and patches of the area. The technology
is not hampered by day / night or weather.
It is recommended that this project i.e. provision
of field control should be provided under the
supervision of State Government / Government of
India in a Public-Private Participation mode.
The whole process
should be well documented. |
| Provision of
Heights |
In addition,
height Bench-marks should be provided on the GPS
stations. Presently, no heights are shown on cadastral
maps. It is envisaged that heights will have good
utility for irrigation projects etc. It is, therefore,
recommended that suitable amendments to the present
specifications should be made in the State Manuals. |
| Contents of
Cadastral Map-use of Aerial Photography |
Traditional
methods of creating map-contents have been ground-basedmethods
of plane-tabling and / or actual measurements
of the plot (followed in Field Measurement Book).
These methods have their own shortcoming of inaccuracy
etc. But the traditional methods need not be criticized
as these have stood the test of time and courts.
It is only now that newer technologies are available
as replacement of the old technology.
The field methods have been replaced by the aerial
photography (Photogrammetry for urban cadastre)
and has been extensively used by Madhya Pradesh
and some other States. A process known as `Rectification
of aerial photography has been adopted by Madhya
Pradesh. In this process the positional inaccuracy
of land feature is removed. The condition is that
the terrain has to be free from major undulations.
Technically, rectification removes the distortions
due to `tilt’ of aerial photography. |
| Orthophoto Mapping |
Orthophoto
is an aerial image (aerial photograph) from where
all the distortions, which adversely affect the
geometry of the photograph, have been removed.
These distortions are due to inherent `tilt’
of aerial photograph and the `relief’ (elevated
/ undulated terrain) of the objects on the ground.
The process of `rectification of aerial photograph
practised in Madhya Pradesh suffers because of
the errors due to relief. The rectification is,
therefore, not recommended for the terrain, which
is highly undulated or hilly.
Thus Orthophoto technology will be an acceptable
and recommended technology for future cadastral
surveys.
The productivity i.e. the reduction of the cost
(one third) and increase in production (2 to 3
times) will make this technology soft on budget.
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| Updating the
Cadastral Maps |
In view
of the legal importance of the cadastral maps
which are invariably referred to in matters of
compensation for land acquisition etc, the updating
is not only necessary but vital. Administratively,
this process can be best performed by the persons
who are already engaged in the preparation of
records. If the original cadastral map has been
well supported by GPS and Orthophoto technologies,
the updating
of the map becomes quite easy.
The above recommended technological processes
lead us to reach to more intense technical discussions.
These are motivated primarily due to useful satellite
based technologies. |
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| Role of High Resolution
Satellite Imagery |
Presently
two commercial satellites with one-metre resolution
are available from USA. The imagery is distributed
by National Remote Sensing Agency, Hyderabad.
From surveying point of view it should be noted
that imagery of 1 metre resolution is able to
give a Planimetric accuracy of about 3-4 metres
[ 1 ] and that too when one uses the precise (costly)
version of the imagery. Therefore, the imagery
may not neccesarily be suitable for producing
original cadastral records.
This imagery is, however, quite useful in updating
1:4000 scale cadastral records, especially those
which have been based on more accurate technology
of aerial photography or precise ground methods.
The use of IKONOS, Digital Globe of USA and in
future, Cartosat of India has to be appreciated
in the light of limitations and effectiveness:
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| Achievable Accuracies |
GPS in
differential mode will generally be able to provide
accuracies of less than 5 cms to the control points.
This is more than adequate for cadastral surveys.Map
on 1:4000 Scale Produced by Accurate Ground Method.
Considering a point of 0.2 mm on the map of 1:4000
scale, the smallest possible dimension determined
on the ground will be: |
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Aerial
Photograph on 1:20000 scale to Produce 1:4000
Scale Cadastral Map – Orthophoto (digital).
Considering accuracy of 20 microns on the negative
scale of 1:20000, the smallest dimension on the
ground (represented by 1:4000 map scale)
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taking
into account the other errors due to photogrammetric
processes (of aerial triangulation and Digital
Terrain Model), the accuracy can be taken as 60
cms.
High Resolution Satellite Imagery 3 to 4 Metres
as established by research papers. See references
[ 1 ].
Height Accuracy of Aerial Photo 0.1 per thousand
feet of flying height; scale 1:20000 |
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Therefore,
contours can be drawn at (1.0 x 5) 5 feet, say
2 metres contour interval. |
| Methodology in Brief |
Based on
the above discussions, the recommended methodology
is given below:Aerial Photography At 1:20000 scale;
black and white
GPS Control (Differential GPS) All tri-junctions
and some more identifiable
points are controlled. Sketches of the points
are made. GPS will provide X, Y and Z coordinates
of the points in terms of WGS 84 system. The Z
can be ignored as the values are not in terms
of spirit levelling procedures.
Photogrammetric Process – Aerial Triangulation
and Digital Terrain Model (DTM) After this operations
all model / overlaps would have control points.
One can resort to Photogrammetry or digital Orthophoto
Mapping
Digital Orthophoto Mapping Recognised Orthophoto
Mapping software(s) can be utilized to produce
images which are true substitute of maps.
Cadastral Records Not all what is shown on an
image is relevant. The property / parcel numbers
have to be identified on the photo / image by
revenue authorities.
Cadastral Map The line-cadastral or digital cadastral
map will be prepared after the properties are
identified by tracing or digitising.
Ground / Field check by Revenue Officials Revenue
officials will make sure that all properties are
taken care of attribute information can also be
verified and completed at this stage.
Optional Work
• Heights of Objects can be surveyed
• Other information about soil, vegetation
etc can also be picked up from photos and verified
on ground. |
| Cost Aspect of the
Methodology |
The break
up of the cost is as follows:
• Aerial Photography The cost depends on
the location of the town and its distance from
Hyderabad, from where the aircraft commences the
flight. As a guide, the cost at Delhi will range
from Rs 40 to Rs 50 per hectare.
• GPS control and other field surveys e.g.
levelling cost range – about Rs 60 to Rs
70 per hectare.
• Digital Orthophoto Mapping Range ….
about Rs 100 to Rs 125 per hectare
• Field / Ground Verification Along without
attribute data – Rs 20 to Rs 30 per hectare
Taking the overall cost, it will range from Rs
175 to Rs 200 per hectare. For comparison the
cost in a case study of similar nature done in
Khamam District of Andhra Pradesh came to Rs 165
per hectare in late nineties. |
| Recommendations |
What is recommended in this paper is the technical
aspect of cadastral surveys which is appropriate,
modern, acceptable, practical and will provide
a big push to the profession of cadastral surveys.
The sound base will be given by the technology
which eventually will reduce the ambiguity regarding
recordsThis technology can be practised in the
model o f Public-Private-Participation (PPP).
The State Government Departments need not spend
huge money in procuring of equipment and instruments.
It is recommended that at initial stages, and
in order to increase acceptability of the technology,
the job should be done in some selected Taluks
as Pilot Project. The technology can be transferred
to States after adequate confidence is built
up in State Cadastral Organizations. The Survey
of India should take a lead role in the introduction
of technology,
say, up to establishment of ground control by
GPS. The resources generated by private sector
in Geomatics can be harnessed through appropriate
PPP model.
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| References |
1. Davis,
Curt.H; “Planimetric Accuracy of IKONOS,
1 metre Panchromatic Image Products” University
of Missouri-Columbia
2. Dikshit, Sanjay; “Integration of Satellite
Survey Techniques…..”; Paper in LIS
National Conference, Oct 2000 organized by CSDMS,
NOIDA.
3. Misra, Prabhakar; “Cadastral Surveys
in India A Critique”; Paper in LIS National
Conference 2000.
4. Upadhaya, A; “Statewide Digital Data
Base and GIS of Cadastral maps, Paper in GIS Development,
Dec 2000. |
|
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Prof
P Misra
Consultant, Land Information Technologies,
New Delhi, India
misralit@hotmail.com |
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| June 2005 |
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